Locating holes in tubing

ABSTRACT

Leaks in underground conduit, such as vertical drill pipe in wells or underground pipelines, are located by closing one end of a segment of the conduit and then pumping a plug into the pipeline. As long as fluid is escaping from the conduit through the leak, the plug will move, but when the plug passes the leak, the plug will no longer move because of the fluid trapped between the plug and the closure. Then the plug can be located by a wire line attached to the plug. If the plug is to be retrieved by pulling the plug, a passageway through the plug is opened to prevent swabbing the conduit when retrieving the plug.

United States Patent [451 Oct. 10,1972

Primary Examiner-Louis R. Prince Assistant Examiner-William A. Henry, HAttorney-Charles W. Coffee [57] ABSTRACT Leaks in underground conduit,such as vertical drill pipe in wells or underground pipelines, arelocated by closing one end of a segment of the conduit and then pumpinga plug into the pipeline. As long as fluid is escaping from the conduitthrough the leak, the plug will move, but when the plug passes the leak,the plug will no longer move because of the fluid trapped 7 between theplug and the closure. Then the plug can be located by a wire lineattached to the plug. If the plug is to be retrieved by pulling theplug, a passageway through the plug is opened to prevent swabbing theconduit when retrieving the plug.

6 Claims, 6 Drawing Figures PATENTEDum 10 4912 I111,IIIIIIIII sum 2 0F 3INVENTOR:

P'ATENTEfinm 10 1912 SHEEI 3 BF 3 INVENTOR: GLENN O. HUBBARD LOCATINGHOLES IN TUBING BACKGROUND OF THE INVENTION 1. Field of the InventionThis invention relates to measuring and testing of pipes using fluidunder pressure to locate the position of aknown leak.

2. Description of the Prior Art Apparatus to test underground conduitsuch as well casing for leaks have been known to prior art, e.g.,Mitchell, U.S. Pat. No. 1,572,748. However, such inventions do not showhow to locate the leak once it was discovered. Also, other devices, suchas Henderson, U.S. Pat. No. 1,221,733, and I-Iauk, U.S. Pat. No.3,478,577, disclose means for testing segments of pipe for leaks,however, in each case the segment tested is a short segment and at thetime the tester is testing, he knows what part he is testing; therefore,if there is a leak he knows the location thereof. En Dean et al., U.S.Pat. No. 2,951,362, discloses a mechanism for testing a pipe which has arecording instrument therein, which will record the time that it passesa leak; therefore, under carefully controlled conditions, theapproximate location of the leak could be determined. Also, theEn Deanet al. patent discloses a wheel, which runs against the inside bore ofthe pipe so that the approximate location of the leak-can be determined.

SUMMARY OF THE/INVENTION With pipelines spanning the country, they oftendevelop a leak and in the case of an oil pipeline, often times the oilwill travel along the pipe a considerable distance before it comes tothe surface; therefore, it may be known that there is a leak in thepipeline, but the exact location of the leak may be difficult 'todetermine. Also, the leak may develop at a river crossing wheredownstream indications show that there is a leak, but the location ofthe leak is extremely difficult to determine. In oil wells, the casingor the eduction tube may have a leak. Indications of the leak arereadily apparent, but the location of the leak downhole is not known.

1. New and Different Function My invention is to locate these leaks withextreme accuracy. A segment of the conduit is separated. In the case ofa well, the entire length of the conduit forms a segment. Then one endof the segment is closed. In a pipeline this would customarily be doneby closing a valve. In a well, this is done by setting a closure plugagainst the seating nipple or other projection at the bottom of thewell. Then a traveling plug is pumped into the conduit. Until the plugreaches the leak, the plug will traverse through the pipe because thereis an excape of the fluid in the conduit through the leak. Once the plugpasses the leak, however, the plug will move no more because of thefluid trapped between the plug and the closure. Then the distanceto thetraveling plug is measured by a wire line. In the case of a well, a wireline with an overshot is lowered and attached to a fishing neck on theplug. Measuring devices are well.

known to oil field workers and by the use of conventional equipment, thelength of wire to the plug can be measured readily. Thereafter, the plugis retrieved by pulling it up with the wire line. A valve in the plug isopened so the tubing is not swabbed of the fluid contained therein asthe plug is retrieved. Thereafter, the

closure plug on the bottom can likewise be retrieved by a wire line andthe leak repaired by conventional means, but the repair of the leak isgreatly facilitated because its exact location is now known.

The same procedure can not be followed exactly with a horizontalpipeline because of the difficulty of attaching a wire line to thetraveling plug in the pipe. Therefore, the preferred procedure in thecase of a pipeline is to attach the wire line to the plug before theplug is pumped through the line. When the plug passes the leak, itstops. The plug could be retrieved by pulling it back with the wireline, however, in pipeline practice the more conventional practice wouldbe to free the wire line from the plug by breaking a shear pin betweenthe wire line and the plug. Then the valve in the end of the segment isopened and the plug is pumped through the line as is standard practicewith pipeline procedures.

2. Objects of this Invention An object of this invention is to locatethe position of a leak in underground conduit.

Further objects are to achieve the above with hardware that is sturdy,compact, durable, simple, safe, lightweight, versatile, efficient andreliable, yet inexpensive and easy to manufacture, install, operate, andmaintain.

Still further objects are to achieve the above with a method that issafe, rapid, versatile, efficient, and inexpensive, and does not requireskilled people to install, adjust, operate, and maintain.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic representation ofan eduction tube in an oil well having a leak to be located.

FIG. 2 is a schematic representation similar to FIG. 1 with-the closureplug in place.

FIG. 3 is a schematic representation similar to FIGS. 1 and 2 with thetraveling plug in place.

FIG. 4 is a view similar to FIGS. 1, 2, and 3, illustrating thetraveling plug being retrieved.

FIG. 5 is a schematic representation of a pipeline with a traveling plugin transit, with axial lengths greatly foreshortened for clarity.

FIG. 6 is a schematic representation similar to FIG. 5 of a pipelinewith a traveling plug in transit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodimentillustrated in FIGS. 1-4 is for locating a leak in an oil well. As maybe seen, some sort of tubular conduit 10 extends deep within the ground.The tubular conduit more than likely would be an eduction tube, however,it will be understood that it could be drill pipe or casing or any otherkind of pipe or tubing which extends underground. Inasmuch as it is morelikely to be an eduction tube of a pumping oil well, it has beenillustrated as such with leak 12 in the form of a hole through thetubing. The length of tubing itself forms a single segment, and at thebottom, the conduit 10 has seating nipple 14 as is common and standardpractice in the oil industrypopen end 16 forms the other end of thesegment.

According to my invention, closure plug 18 is inserted into the tubingand then pump 20 is attached to the open end 16 and the plug 18 ispumped down to the seating nipple 14. This procedure, of course, closesthe closable end, which is in this instance the bottom end of thesegment, which is the conduit 10.

In some instances, the closure plug 18 may be dropped and no pump used,but if a pump is used, thereafter, the pump 20 is disconnected from theopening 16 and traveling plug 22 is placed in the open end 16 of theconduit 10 and the pump 20 reconnected to the conduit and fluid ispumped from behind the plug 22, forcing the traveling plug 22 down theconduit. So long as the fluid within the conduit can escape through theleak 12 ahead of the plug 22, the traveling plug 22 traverses down theconduit. However, immediately when the plug 22 passes the location ofthe leak 12, the plug 22 stops because of the trapped oil or water inthe conduit 10 is non-compressible. Of course there is no way for theoperator to known that the plug 22 has stopped, so he continues pumpinguntil he has displaced sufficient fluid volume in the pump 20 to havepumped the plug all the way to the closable end at the seating nipple14.

Thereafter, the pump 20 is again disconnected from the open end 16 andovershot 24 is attached to wire line 26, which is reeved aroundmeasuring device 28. The measuring device 28 is common in oil well workand is commercially available on the market; they generally consist oftwo pulleys, the wire line going over one and under the other so thereis good frictional contact between the wire line and the pulleys; thenone of the pulleys having a known diameter is connected to a counter sothat the amount of wire line passing over the pulley is known. With theovershot 24 on the wire line 26, the overshot is lowered until theovershot contacts fishing neck 30 on top of the traveling plug 22. Suchprocedures are well known in the oil field and the operator candetermine when the overshot does connect to the fishing neck 30 and atthat time the measurement on the measuring device 28 is noted. Thismeasurement is the distance from the open end 16 of the tubing 10 to theleak 12, which is the desired information. Thereafter, tension upon theline 26 will retrieve the plug 22.

The tension on the fishing neck 30 of the plug 22 will open valve 32located in the passageway 34, which extends axially through the plug 22.(FIG. Opening this passageway as the plug is being pulled out, permitsthe fluid to pass through the plug 22; therefore, the tubing or conduitis not swabbed as the plug is retrieved. Where it not for the valve 32opening the passageway 34 because the sides of the plug make a sealingcontact with interior walls or bore of conduit 10, the pulling of theplug would cause all the fluid in the conduit to be pulled up as theplug was removed or the tubing would be swabbed. This is undesirablebecause of the additional weight or tension on the line 26 and, also,because there is no good disposal of the fluid at the open end 16 of thetubing.

The valve 32 is normally held in a closed position by spring 36.Construction of such plugs is well within the skill of people ordinarilyacquainted with oil wells and is not described further here, except theplug does have the valve 32 actuated from tension upon the fishing neck30, which opens the passageway 34 and that normally the spring 36 holdsthe valve 32 closed, thereby closing the passageway 34. The wipers orcups 38,

which form the seal between the plug and the tubing, are of conventionaldesign.

After the plug 22 is retrieved and removed from the overshot above theground, the overshot 24 is again lowered into the well to engage uponfishing neck 40 of the closure plug 18. The closure plug 18 can be ofidentical construction as the traveling plug 22; therefore, the tensionupon the fishing neck 40 opens valve 42 in a passageway so that thetubing is not swabbed as the closure plug 18 is retrieved. Likewise, aspring (not shown) normally holds valve 42 closed. Thus I provide asimple structure and method to locate precisely where tubing, drillpipe, drill stem, casing, or any other of the tubular conduits in wellsare leaking.

Another embodiment of my invention is illustrated in FIG. 6. In thisparticular instance, the underground conduit is illustrated as apipeline. Such conduits extend for thousands of miles, but in thisparticular instance the invention is concerned only with segment 50between pump or open end 52, and the closable end being represented bygate valve 54. As is standard practice with underground pipelines, thereis means, represented at 56, for removing pigs or plugs, which areconventionally put in the line to separate different fluids which may bepumped therethrough.

To find the location of leak 58, first the line is filled with somenon-compressible fluid and the gate valve 54 is closed. Then travelingplug 60 with wire line 62 attached by means of shear pin 64 isintroduced into the pipeline. Conventionally, packing or wiper 66extends around the wire line to form a seal therearound. The plug 60 ispumped by pump 68 along the pipeline. Until it reaches leak 58, the plugwill continue down the pipeline because of the displacement and loss ofthe fluid between the plug 60 and the gate valve 54.

However, as soon as the plug 60 passes the leak 58, it will move no morebecause of the non-compressible fluid trapped between the plug 60 andgate valve 64 at which time the plug will stop. This will be immediatelyevident to the operator because the wire line 62 will stop being fedinto the packing 66. At that time, a measurement may be made upon thewire line 62 or measurement read in a similar manner as the previousembodiment or the wire line can be marked at that time.

The shear pin 64 is broken by a sudden pull or jerk upon the wire line62, and the wire line retrieved to the open end 52 of the segment 50 ofthe pipeline being tested. Then the valve 54 is opened and the travelingplug pumped on to the removal point 56 where it is removed as plugs areconventionally removed.

Another means of operation is that after the location has been found,the plug 60 is retrieved by pulling the wire line and the plug, both,back to the open end 52. When this procedure is followed, the plug isprovided with an axial passageway and spring biased valve closing sameso that the segment 50 would not be swabbed as the plug was beingretrieved.

Another mode of operation is to cut the wire line 62 at the packing 66at the time the plug 60 stops. Then the valve 54 is opened and the plugwith the wire line attached is pumped on to the removal point 56 and thewire line removed along with the plug.

In any event, by having the wire line attached to the plug and the plugstopped at the leak 58, an exact measurement by the wire line isobtained to find the exact The embodiments shown and described above areonly exemplary. I do not claim to have invented all the parts, elementsor steps described. Various modifications can be made in theconstruction, material, arrangement, and operation, and still be withinthe scope of my invention. The limits of the invention and the bounds ofthe patent protection are measured by and defined in the followingclaims. The restrictive description and drawing of the specific examplesabove do not point out what an infringement of this patent would be, butare to enable the reader to make and use the invention.

l claim as my invention: 1. In a long tubular conduit extendingunderground having a. at least one segment with i. an open end, and ii.a closable end, and a leak in the segment, 0. the improved structure forlocating the position of the leak in the segment comprising: closuremeans for closing the closable end thereat, e. a traveling plugintroduced in the. segment from the open end thereof, f. pump means forpumping fluid into the conduit at the open end, a line extending in theconduit from the open en to the plug, a fishing neck on the travelingplug, 1. an axial fluid passageway through the traveling plug, and Ivalve means attached to the fishing neck for opening the passageway whentension is applied to the fishing neck so that the conduit is notswabbed as the plug is pulled. 2. The invention as defined in claim 1with the additional limitations of m. a seating nipple at said closableend of the segment and n. said closure means being a closure plug whichis pumped into the conduit against the seating nipple.

3. The invention as defined in claim 1 with the additional limitationsof r h. measuring means connected to the line outside the conduit formeasuring the length of the line in the conduit.

4. The invention as defined in claim 3 with the additional limitation ofn. a seating nipple at said closable end of the segment and 0. saidclosure means being a closure plug which is pumped into the conduitagainst the seating nipple.

5. The method of locating the position of a leak in a long tubularconduit comprising the steps of:

a. filling a segment of the conduit with non-compressible fluid,

b. closing the end of the segment of the tubular conduit,

c. pumping a traveling plug into an open end of the conduit by i.introducing the plug into the segment, and ii. pumping fluid behind thel u d. continuing to pump fluid be lll' the plug until the plug couldreach the end of the segment, and then e. retrieving the traveling plugby f. pulling it back to the open end of the conduit by a line attachedto the plug, and

. g. measuring the length of line extended, thus h. measuring thedistance of the plug from the end of the segment where the plug wasintroduced;

j. opening a valve in the plug responsive to pulling the plug, thus k.preventing the plug from swabbing the conduit as it is removed.

6. The invention as defined in claim 5 with the additional limitationsof j. attaching the line to plug after the pumping operation iscompleted.

1. In a long tubular conduit extending underground having a. at leastone segment with i. an open end, and ii. a closable end, and b. a leakin the segment, c. the improved structure for locating the position ofthe leak in the segment comprising: d. closure means for closing theclosable end thereat, e. a traveling plug introduced in the segment fromthe open end thereof, f. pump means for pumping fluid into the conduitat the open end, g. a line extending in the conduit from the open end tothe plug, h. a fishing neck on the traveling plug, j. an axial fluidpassageway through the traveling plug, and k. valve means attached tothe fishing neck for opening the passageway when tension is applied tothe fishing neck so that the conduit is not swabbed as the plug ispulled.
 2. The invention as defined in claim 1 with the additionallimitations of m. a seating nipple at said closable end of the segmentand n. said closure means being a closure plug which is pumped into theconduit against the seating nipple.
 3. The invention as defined in claim1 with the additional limitations of h. measuring means connected to theline outside the conduit for measuring the length of the line in theconduit.
 4. The invention as defined in claim 3 with the additionallimitation of n. a seating nipple at said closable end of the segmentand o. said closure means being a closure plug which is pumped into theconduit against the seating nipple.
 5. The method of locating theposition of a leak in a long tubular conduit comprising the steps of: a.filling a segment of the conduit with non-compressible fluid, b. closingthe end of the segment of the tubular conduit, c. pumping a travelingplug into an open end of the conduit by i. introducing the plug into thesegment, and ii. pumping fluid behind the plug, d. continuing to pumpfluid behind the plug until the plug could reach the end of the segment,and then e. retrieving the traveling plug by f. pulling it back to theopen end of the conduit by a line attached to the plug, and g. measuringthe length of line extended, thus h. measuring the distance of the plugfrom the end of the segment where the plug was introduced; j. opening avalve in the plug responsive to pulling the plug, thus k. preventing theplug from swabbing the conduit as it is removed.
 6. The invention asdefined in claim 5 with the additional limitations of j. attaching theline to plug after the pumping operation is completed.